#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("Ofast,inline") // Ofast = O3,fast-math,allow-store-data-races,no-protect-parens
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("bmi,bmi2,lzcnt,popcnt") // bit manipulation
#pragma GCC target("movbe") // byte swap
#pragma GCC target("aes,pclmul,rdrnd") // encryption
#pragma GCC target("avx,avx2,f16c,fma,sse3,ssse3,sse4.1,sse4.2")
typedef long long ll;
#define rep(i, a, b) for (int i = (a); i < int(b); i++)
#define rrep(i, a, b) for (int i = (a) - 1; i >= int(b); i--)
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
#define pb push_back
#define all(x) x.begin(), x.end()
inline void fast() { ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); }
ll INF = 1000000000;
ll mod = 1e9 + 7;
#define int ll
#define float double
//
int N;
vector<int> ns;
vector<pii> splits;
int32_t main()
{
fast();
cin >> N;
ns.assign(N, -1);
rep(i,0,N) {
cin >> ns[i];
}
int hn = N / 2;
int sum1 = 0, sum2 = 0;
rep(i,0,hn) {
sum1 += ns[i];
}
rep(i,hn,N) {
sum2 += ns[i];
}
rep(i,0,N) {
splits.pb({sum1, sum2});
//
sum2 += ns[i];
sum1 -= ns[i];
sum1 += ns[(i + hn) % N];
sum2 -= ns[(i + hn) % N];
//
}
int bans = 0;
multiset<int> s;
rep(i,0,N % 2 ? hn + 1 : hn) {
s.insert(splits[i].second);
}
// rep(i,0,N) {
// cerr << splits[i].first << " " << splits[i].second << "\n";
// }
rep(i,0,N % 2 ? 2*N : N)
{
// cerr << "*";
auto x = s.begin();
int ans = *x;
bans = max(bans, ans);
if (N % 2) {
s.erase(s.lower_bound(splits[i % N].second));
s.insert(splits[(i + hn + 1) % N].second);
}
else {
s.erase(s.lower_bound(splits[i % N].second));
s.insert(splits[(i + hn) % N].second);
}
}
cout << bans << "\n";
}
